HowTo: Use OAuth2PasswordGrant + alamofire + own authorize loginscreen

[ItsMeSandu]

Sorry for this question but I tryhard since 2 days 🙄

I have 4 components:

• ViewController
• LoginViewController
• OAuthHandler
• OAuth2RetryHandler (from alamofire)

ViewController:

class ViewController: UIViewController {
	
    var loginHandler: LoginHandler?

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
		
	loginHandler = LoginHandler(clientId: CLIENT_ID, clientSecret: CLIENT_SECRET)
	loginHandler?.authorize(view: self, completion: { (response) in
	    print(response)
	})
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

}

LoginViewController: currently just a blank UIViewController

OAuth2RetryHandler: is just copied from the sample

OAuthHandler:

class OAuthHandler: OAuth2PasswordGrantDelegate {
    var oauth2: OAuth2PasswordGrant
    fileprivate var alamofireManager: SessionManager
	
    public init(clientId: String, clientSecret: String) {
        oauth2 = OAuth2PasswordGrant(settings: [
		"client_id": clientId,
		"client_secret": clientSecret,
		"token_uri": TOKEN_URI,
		"keychain": true,
		"verbose": true
        ] as OAuth2JSON)
    
        let sessionManager = SessionManager()
        let retrier = OAuth2RetryHandler(oauth2: oauth2)
	sessionManager.retrier 	= retrier
	sessionManager.adapter	= retrier
	alamofireManager = sessionManager
		
	oauth2.delegate = self
    }
    
    public func authorize(view: UIViewController, completion: @escaping ( OAuth2JSON? ) -> Void) {		
	oauth2.authConfig.authorizeEmbedded = true
	oauth2.authConfig.authorizeContext = view

        alamofireManager.request("https://api.github.com/user").validate().responseJSON { (response) in
	    debugPrint(response)
	    if let dict = response.result.value as? [String: Any] {
	       print(dict)
	    }
	    else {
	       print(OAuth2Error.generic("\(response)"))
	    }
	}
    }

    public func loginController(oauth2: OAuth2PasswordGrant) -> AnyObject {
        if let vc = oauth2.authConfig.authorizeContext as? UIViewController {
		vc.present(LoginViewController(), animated: true, completion: nil)
		return vc
	}
	return LoginViewController()
    }
}

---

For this build I get the following error:

[Debug] OAuth2: Initialization finished
[Debug] OAuth2: Looking for items in keychain
[Debug] OAuth2: Initialization finished
[Debug] OAuth2: Starting authorization
[Debug] OAuth2: No access token, checking if a refresh token is available
[Debug] OAuth2: Error refreshing token: I don't have a refresh token, not trying to refresh
[Debug] OAuth2: Presenting the login controller
2018-03-01 13:56:54.497130+0100 LibAccount_Example[424:81789] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Application tried to present modal view controller on itself. Presenting controller is <LibAccount_Example.ViewController: 0x102216aa0>.'

[ItsMeSandu]

My current solution looks like the following:

My 4 components:

• BasicViewController
• CustomLoginViewController
• OAuth2RetryHandler
• LoginHandler

BasicViewController:

    class BasicViewController: UIViewController {
        var loginHandler: LoginHandler?

        override func viewDidLoad() {
            super.viewDidLoad()

            // Do any additional setup after loading the view.
            loginHandler = LoginHandler(clientId: OAUTH_CLIENT_ID, clientSecret: OAUTH_CLIENT_SECRET)
        }
	
        override func viewDidAppear(_ animated: Bool) {
          super.viewDidAppear(animated)
          let userLoggedIn = UserDefaults.standard.bool(forKey: "LOGGED_IN")
		
          let token = loginHandler?.oauth2.accessToken

          if (!userLoggedIn) || (userLoggedIn && token == nil) {
          	loginHandler?.authorize(presenting: self)
          }
        }
	
        public func logout() {
          loginHandler?.logout()
          self.viewDidAppear(true)
        }

        @objc internal func handleLogoutButton(sender: UIButton) {
  	     logout()
        }
    }

    extension BasicViewController: OAuth2PasswordGrantDelegate {
        public func loginController(oauth2: OAuth2PasswordGrant) -> AnyObject {
        	return CustomLoginViewController(oauth: oauth2)
        }
    }

CustomLoginViewController:

    open class CustomLoginViewController: UIViewController {
        // MARK: - object-properties
        fileprivate var oauth: OAuth2PasswordGrant?

        // MARK: - system-methods
        public init(oauth: OAuth2PasswordGrant) {
          self.oauth = oauth
        	super.init(nibName: nil, bundle: nil)
        }

        required public init?(coder aDecoder: NSCoder) {
        	super.init(coder: aDecoder)
        }

        override open func viewDidLoad() {
          super.viewDidLoad()

          // Do any additional setup after loading the view.
        }
    }

OAuth2RetryHandler: is just copied from the sample

LoginHandler:

    open class LoginHandler {
      public var oauth2: OAuth2PasswordGrant
      open var alamofireManager: SessionManager

      public init(clientId: String, clientSecret: String) {
      	
        oauth2 = OAuth2PasswordGrant(settings: [
        	"client_id": clientId,
        	"client_secret": clientSecret,
        	"token_uri": TOKEN_URI,
        	"keychain": true,
        	"grant_type": "password",
        	"scope": "",
        	"verbose": true
        ] as OAuth2JSON)
      	
        let sessionManager = SessionManager()
        let retrier = OAuth2RetryHandler(oauth2: oauth2)
        sessionManager.retrier 	= retrier
        sessionManager.adapter	= retrier
        alamofireManager = sessionManager
      }

      public func authorize(presenting view: UIViewController) {
        // as far as I know now, the following if-request is not necessary
        // because "authorizeEmbedded" is checking it already
        if oauth2.isAuthorizing {
        	oauth2.abortAuthorization()
        	return
        }

        if let view = view as? OAuth2PasswordGrantDelegate {
        	oauth2.delegate = view
        }

        oauth2.authorizeEmbedded(from: view) { (authParameters, error) in
        	if let _ = authParameters {
        		print(authParameters)
        		UserDefaults.standard.set(true, forKey: "LOGGED_IN")
        	}
        	else {
        		UserDefaults.standard.set(false, forKey: "LOGGED_IN")
        		print("Authorization was canceled or went wrong: \(String(describing: error?.description))")
        	}
        }
      }

      public func logout() {
        oauth2.forgetTokens()
        oauth2.username	= nil
        oauth2.password	= nil
        UserDefaults.standard.set(false, forKey: "LOGGED_IN")
      }
    }

[TheSwiftyCoder]

@PetresS - Did you manage to solve this issue?

[ItsMeSandu]

@TheSwiftyCoder yes I did. The 2nd comment is my current solution, but I'm not sure if my solution is a "best practice"-solution.

I would appreciate if someone could post a best-practice-sample.

[AndersonAltissimo]

@PetresS

Your solution gave me north, but I think I'm doing something wrong because my login screen did not render :(

I don't know what can be.

[ItsMeSandu]

@AndersonAltissimo

did you solve your problem? sorry for late response :(

[AndersonAltissimo]

@PetresS

No problem man I solved the problem 👍

[grEvenX]

Struggling with the same, the documentation could need a fair share of updating here. There's no description of the flow of how you are supposed to work with the delagate and perform the actual login.